Peace talks aimed at ending the Syrian conflict have wrapped up in Geneva, with both sides blaming each other for the lack of a firm agreement.

"The gap between the sides remains wide. There is no use pretending otherwise," said United Nations Arab mediator Lakhdar Brahimi, who has tirelessly pursued a peace deal that other diplomats consider "mission impossible".

Neither the Syrian government or the opposition has been willing to budge from their main positions.

The government wants to talk about fighting "terrorism" - a word it uses to refer to all its armed foes.

Syrian foreign minister Walid al-Moualem blamed the lack of tangible results on what he called the immaturity and narrow composition of the opposition delegation, as well as US interference.

"There are huge divides between (the opposition delegation) and what happening on the ground in Syria," he said.

"They are not in touch with what is taking place in Syria... and have no control over anybody on ground."

The opposition wanted the talks to focus on a transitional administration it says will remove President Bashar al-Assad from power.

The Friends of Syria, an alliance of mainly Western and Gulf Arab states, blamed the Syrian government for the lack of diplomatic headway.

"It must not further obstruct substantial negotiations and it must engage constructively in the second round of negotiations," the group said in a statement.

With so many groups adding their names to those opposing the current regime, take a look at some of the most prominent.

Expectations had always been low for a breakthrough on political issues at the talks, the first between Assad's representatives and his foes in an almost three-year-old conflagration that has killed 130,000 Syrians and driven a third of the population from their homes.

The sides could not even achieve more modest goals, such as an agreement to allow aid convoys into Homs, where thousands of civilians are trapped with no access to food or medicine.

"Homs was extensively discussed, although unfortunately there has been no breakthrough yet," Mr Brahimi said.

Still, the sides took a first tentative step forward on Wednesday by agreeing to use a 2012 document as a basis for discussions.

Furthermore, Mr Brahimi said he had observed some common ground between the opposing delegations and simply having them sharing the same room has been a minor victory.

"Progress is very slow indeed, but the sides have engaged in an acceptable manner," he said.

Mr Brahimi said the opposition delegation would be back in 10 days for a second round of talks.

But Mr Assad's delegates had told him they would have to check with Damascus before agreeing to return.

"They didn't tell me that they are thinking of not coming. On the contrary, they said that they would come but they needed to check with their capital," Mr Brahimi told a news conference.

US State Department said the Syrian government "continues to play games" with its non-committal stance to future talks, while the opposition had shown it was serious in pledging to return to the table.

"The people of Syria are watching and will determine who truly has their best interests at heart," said spokesman Edgar Vasquez.

"The Syrian people, who have suffered so much, deserve constructive engagement now and in the next round," Mr Vazquez said.

Chemical weapons delay

Darkening the atmosphere further, the US and Russia clashed over the pace of Syria's handover of chemical arms for destruction.

"The United States is concerned that the Syrian government is behind in delivering these chemical weapons precursor materials on time with the schedule that was agreed to," said US Defence Secretary Chuck Hagel.

Moscow rejected the US accusations and blamed security on the road to the Mediterranean coast for the delays.

"We see that the Syrians are approaching the fulfilment of their obligations seriously and in good faith," said Russian Foreign Ministry official Mikhail Ulyanov, according to Interfax news agency.

"Our American partners, in their usual manner, are betting on pressure even in those cases where there is absolutely no need for it."

There have been reports earlier in the week that Syria had given up less than five per cent of its chemical weapons arsenal and will miss a deadline next week to send all toxic agents abroad for destruction.

Relentless carnage

The Syrian Observatory for Human Rights, a Britain-based monitoring group, said 1,870 people had been killed during the week of talks, including 450 civilians and 40 who died from inadequate access to food and medicine in areas besieged by government troops.

With few achievements on substance, diplomats say the priority now is just to keep the talks process going in the hope that rigid positions can be modified over time.

Mr Assad's forces have recaptured territory, reducing pressure on him to compromise. Western states that once brandished the threat of intervening against him abandoned such plans last year.

The insurgents have become increasingly divided and Islamic militants have gained power on the ground - they refused to attend the talks.

The United Nations invited Mr Assad's main Middle East ally Iran at the last minute, then reversed and revoked the offer.

Thursday's final negotiating session began with a rare gesture of harmony when all sides observed a minute's silence for the 130,000 people killed during the war.

"All stood up for the souls of the martyrs. Symbolically it was good," said opposition delegate Ahmad Jakal.